how to use SocketAsyncEventArgs in unity3d

our game have to support wp8 platform, so i have to use SocketAsyncEventArgs rewrite my communication logic, but when i use SocketAsyncEventArgs in unity3d i can't get message exactly from server,here is my logic,please help me, Thanks!

 public class NewBehaviourScript : MonoBehaviour
 {
     SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
     static IPAddress address = IPAddress.Parse("192.168.1.200");
     static IPEndPoint hostEntry = new IPEndPoint(address, 3699);
     //static IPAddress address = IPAddress.Parse("192.168.1.201");
     //IPEndPoint hostEntry = new IPEndPoint(address, 7777);
     public static Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
     // Use this for initialization
     void Start()
     {
         socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(SocketEventArg_Completed);
 
         socketEventArg.RemoteEndPoint = hostEntry;
         socketEventArg.UserToken = sock;
         sock.ConnectAsync(socketEventArg);
     }
 
     // Update is called once per frame
     void Update()
     {
 
     }
     void OnGUI()
     {
         if (GUI.Button(new Rect(0, 0, 100, 20), "click"))
             Send();
     }
     static void SocketEventArg_Completed(object sender, SocketAsyncEventArgs e)
     {
         switch (e.LastOperation)
         {
             case SocketAsyncOperation.Connect:
                 ProcessConnect(e);
                 break;
 
             case SocketAsyncOperation.Receive:
                 ProcessReceive(e);
                 break;
 
             case SocketAsyncOperation.Send:
                 ProcessSend(e);
                 break;
 
             default:
                 throw new Exception("Invalid operation completed");
         }
     }
     private static void ProcessConnect(SocketAsyncEventArgs e)
     {
         if (e.SocketError == SocketError.Success)
         {
             // Successfully connected to the server
             Debug.Log("connect success");
         }
         else
         {
             throw new SocketException((int)e.SocketError);
         }
     }
     void Send()
     {
         SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
         socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(SocketEventArg_Completed);
         socketEventArg.RemoteEndPoint = hostEntry;
         socketEventArg.UserToken = sock;
 
         byte[] buffer = Encoding.UTF8.GetBytes("Hello World");
         socketEventArg.SetBuffer(buffer, 0, buffer.Length);
 
         bool willRaiseEvent = sock.SendAsync(socketEventArg);
 
         if (!willRaiseEvent)
         {
             ProcessSend(socketEventArg);
         }
     }
     private static void ProcessReceive(SocketAsyncEventArgs e)
     {
         if (e.SocketError == SocketError.Success)
         {
             // Received data from server
             Debug.Log("get from server" + Encoding.UTF8.GetString(e.Buffer));
         }
         else
         {
             throw new SocketException((int)e.SocketError);
         }
     }
     static void ProcessSend(SocketAsyncEventArgs e)
     {
         if (e.SocketError == SocketError.Success)
         {
             //Read data sent from the server
             Socket sock = e.UserToken as Socket;
             bool willRaiseEvent = sock.ReceiveAsync(e);
 
             if (!willRaiseEvent)
             {
                 ProcessReceive(e);
             }
         }
         else
         {
             throw new SocketException((int)e.SocketError);
         }
     }
 }